A Connecticut school board has vowed to investigate a high school senior’s claim that his school blocked conservative-leaning websites while allowing full access to sites on the left.

Andrew Lampart was researching gun control in May for his studies at Nonnewaug High School in Woodbury, but was unable to view the National Rifle Association’s website from a school computer, he told FoxCt.com. But he had no problem getting the other side of the gun control debate from sites like Moms Demand Action and Newtown Action Alliance, he told the school board, which pledged on Wednesday to investigate.

Lampart, 18, said the problem didn’t end with the gun-control issue. When he tried to access the state’s GOP website, he was blocked, but he was able to read any item he wanted to on the state’s Democratic Party’s website, he said.

Lampart claims the issue went even further down the political divide, to issues including abortion and religion. He told the station he had full access to Planned Parenthood’s website, but could not access pro-life groups’ websites. He was also blocked from Christianity.com and the Vatican’s website, but not Islam-guide.com, he said.

“They’re trying to, in my opinion, shelter us from what’s actually going on around the country and around the world by blocking these websites,” Lampart said. “It should be the other way around. The websites should be unblocked so that students can get different viewpoints from different sides of each argument.”

The Woodbury school district issued a statement Thursday, saying that it pressed Dell SonicWall, its filtering provider, as to why the liberal websites fell into a “not rated” category and the conservative sites fell into “political/advocacy group” category, barring them from school computers.

“The district is trying to determine the reason for the inconsistency and if the bias is pervasive enough to justify switching to another content filtering provider,” the statement read. “The district does not block individual sites, only categories of websites. The categories are supposed to be inclusive of all sites that fall into a common description. The district does engage in unblocking sites to provide diverse points of view and balance in the instructional process.”